Abstract: Carbon fiber including graphitized fiber is processed electrochemically in an acidic solution for a time sufficient to run a layer reaction such that the reaction extends to the inside of the fiber and thereafter, as required, heat-treated accurately at 100° C. or more to expand layer spacing to form multifibrous carbon fiber, with which hydrogen is brought into contact, adsorbing hydrogen in the inside of the multifibrous carbon fiber.

Abstract: Carbon fiber including graphitized fiber is processed electrochemically in an acidic solution for a time sufficient to run a layer reaction such that the reaction extends to the inside of the fiber and thereafter, as required, heat-treated accurately at 100° C. or more to expand layer spacing to form multifibrous carbon fiber, with which hydrogen is brought into contact, adsorbing hydrogen in the inside of the multifibrous carbon fiber.

Abstract: A carbon-fiber-reinforced composite material is simply produced by molding a resin composition comprising carbon fibers and a matrix resin directly on a base material through injection molding or compression molding without resort to any primer.

Abstract: A carbonaceous preform, which is free from such drawbacks as delamination and is superior in formability and mass productivity, can be obtained by a process comprising the steps of fixing a laminate of stacked carbon fibers with a fixing jig in the absence of a binder, impregnating the thus-fixed laminate with a molten carbonaceous pitch, and carbonizing the impregnated laminate in a non-oxidative gas atmosphere.

Abstract: A process for producing a process for producing a two- or three-dimensional carbon fabric, which process includes melt-spinning (a) an optically anisotropic carbonaceous pitch having an optically anisotropic phase content of 60 to 100%, subjecting the thus- infusibilized fibers to a primary heat treatment at a temperature greater than 1000.degree. and not higher than 2500.degree. C. to produce primary heat treated fibers having a tensile strength not lower than 300 kg/mm.sup.2 and a breaking elongation in the range of 0.4% to 10%, preparing a two- or three-dimensional fabric from the primary heat treated fibers and then subjecting the two- or three-dimensional fabric to a secondary heat treatment at a temperature which is at least 50.degree. higher than the temperature used in the primary heat treatment, the temperature in the secondary heat treatment being higher than 1050.degree. C. and no higher than 3300.degree. C.

Abstract: A carbon/carbon composite is prepared without using any expensive carbon fiber fabric and without performing any complicated molding step prior to a densifying step. More specifically, a pitch-based infusiblized fiber alone, or optionally in the form of a mixture thereof with a pitch-based carbonized fiber, is subjected to carbonization and molding under uniaxial pressing to obtain a carbon/carbon composite preform. The preform is then densified using a carbonaceous matrix.

Abstract: A process for producing a carbon/carbon composite having a ceramic and carbon coating on its surface consists essentially of the steps of heating a carbon/carbon composite at a temperature of from 800.degree. to 1,700.degree. C., contacting the thus heated composite in the presence of hydrogen with at least one compound selected from the group consisting of halides and hydrides of Si, Zr, Ti, Hf, B, Nb and W in gaseous form to convert the surface of the carbon/carbon composite, in the absence of a carbon releasing gas, into a carbide ceramic layer and then forming a coating film consisting of both carbon and ceramic by vapor phase decomposition at a pressure of 5-100 Torr on said carbide ceramic.

Abstract: A simple manufacturing process for obtaining a carbon/carbon composite of superior performance is provided without using a carbon fiber fabric which is expensive and without going through the step of fixing fibers together using a binder.A precursor fiber for a carbon fiber which precursor fiber has been rendered infusible is subjected to uniaxial pressing at a temperature lower than the temperature adopted in the infusiblizing treatment, and then a carbonization treatment is performed.According to the present invention, a primary-pressed carbon material can be produced without using a binder, thus resulting in that not only the carbon material but also a carbon/carbon composite can be produced in a simple manner.

Abstract: A process of manufacturing carbon fibers of high chemical stability comprises reacting feed carbon fibers having an elastic modulus of 30.times.10.sup.3 kgf/mm.sup.2 with a compound of elements capable of forming a carbide ceramics on the carbon fibers peripherally alone or both peripherally and partially internally.

Abstract: A carbon/carbon composite is prepared by impregnating a bundle of carbon fibers with a polymer of a nitrogen-containing heterocyclic compound, carbonizing the thus-impregnated carbon fiber bundle under pressure or under pressing and, optionally, further carbonizing the thus-carbonized carbon fiber bundle at atmospheric pressure.

Abstract: A carbon/carbon composite is prepared by mixing 100 parts of a carbonaceous pitch with 1-45 parts by weight of at least one aromatic compound containing at least one functional group selected from nitro and hydroxyl groups, then impregnating a bundle of carbon fibers with the resulting mixture, thereafter carbonizing the thus-impregnated carbon fiber bundle under pressure or under pressing, and if necessary, further carbonizing the thus-carbonized carbon fiber bundle at atmospheric pressure.

Abstract: A carbon/carbon composites is produced by impregnating a tow of carbon filaments with a carbonaceous pitch, placing the impregnated tow in an open container, then subjecting it to a heat treatment under hot isostatic pressing.

Abstract: A carbon material having oxidation resistance is prepared by forming a fi coating constituted mainly by carbon on the surface of a carbon/carbon composite by chemical vapor deposition, then forming on said first coating a second coating of a ceramic or both a ceramic and carbon by chemical vapor deposition, and changing at least one of thermal physical properties or mechanical physical properties of carbon in said first coating continuously or step-wise.

Abstract: A carbon/carbon composite is produced by impregnating a primary-formed product consisting essentially of carbon fibers and a carbonized or graphitized matrix with a carboneceous pitch, heat-treating the thus-impregnated primary-formed product under hot isostatic pressing and carbonizing or graphitizing the thus heat-treated primary-formed product.

Abstract: A carbon/carbon composite having oxidation resistance is produced by filling the voids of a carbon/carbon composite comprising 10-70% by volume of carbon fibers and 5-90% by volume of a carbonaceous matrix and having a void percentage of 10-55%, with at least one of carbon and a ceramic by chemical vapor infiltration and then coating the deposit surface with a ceramic or both ceramic and carbon by chemical vapor deposition.

Abstract: A process for fabricating a carbon/carbon fiber composite characterized in that one or more kinds of fibers selected from the group consisting of a pitch fiber obtained by spinning a carbonaceous pitch, an infusiblized fiber obtained by subjecting the pitch fiber to an infusiblizing treatment, and a pre-carbonized fiber obtained by subjecting the infusiblized fiber to a pre-carbonizing fiber at 400.degree. to 800.degree. C. in an inert gas atmosphere, are woven, laminated or mix-pulverized together with a pitch-based carbon fiber, and then carbonized under the application of pressure or under pressing.

Abstract: In a process for producing carbon fibers from a carbonaceous pitch, the improvement characterized in that an end portion of infusiblized fiber or carbonized fiber to be first subjected to a carbonizing or graphitizing treatment and that of infusiblized fiber or carbonized fiber to be next subjected to the same treatment are bonded together using a composition comprising (a) at least one member selected from the group consisting of phenolic resins and pitches and (b) graphite powder, and the thus-bonded fibers are fed successively to a carbonizing apparatus or a graphitizing apparatus.

Abstract: In the process for producing pitch carbon fibers by melt-spinning a carbonaceous pitch, and infusiblizing the resulting pitch fibers followed by carbonization and, additionally as needed, graphitization, the pitch fibers are subjected to infusiblization treatment following application of a dimethyl polysiloxane having a viscosity at 25.degree. C. in the range between 0.5 and 500 cSt and removing said dimethyl polysiloxane by washing prior to the carbonization.

Abstract: Provided is a process for producing a pitch-based graphite fiber, which process comprises treating a pitch fiber in an oxidative gas atmosphere to render it infusible, said pitch fiber being obtained by melt-spinning a carbonaceous pitch, then heat-treating the infusibilized fiber at 400.degree.-750.degree. C. in an inert gas atmosphere to obtain a precarbonized fiber substantially containing oxygen, then raising the temperature to 2,000.degree.-3,000.degree. C. at a rate of 500.degree. C. or higher per minute in an inert gas atmosphere and heat-treating the precarbonized fiber at the raised temperature of 2,000.degree.-3,000.degree. C. in said inert gas atmosphere.

Abstract: A process for producing carbon fibers, comprising melt spinning a carbonaceous pitch to obtain pitch fibers, contacting the thus obtained pitch fibers with hydrobromic acid, making the thus contacted fibers infusible in an oxidizing atmosphere and then carbonizing and, if desirable, graphitizing the thus treated pitch fibers to obtain the carbon fibers.